DE3741401A1 - METHOD FOR PRODUCING SOLID OR PASTE-SHAPED PRODUCTS - Google Patents

Abstract

A process for the production of solid or paste-form products by fast reactions is carried out stoichiometrically wherein a gaseous medium is introduced into each of the reactants to be reacted with one another, the reactant streams formed are combined and are subsequently forced through a spray unit in a weight ratio of gaseous medium to product stream of from 0.04 to 0.3 (kg/kg) and at a rate of 0.1 to 15 m/second, as calculated from the gas-free reactant streams and based on the free cross-section of the spray unit. The products obtained are free from readily volatile constituents.

Description

The invention relates to a method for producing solid or pasty products by implementing stoichiometric Amounts of multiple reactants in a fast-moving Reaction and spraying of the reaction products in one Spraying device.

Typical examples of rapid chemical reactions In the sense of the present invention are neutralization of acids, the saponification of esters and alkylation reactions, especially alkylations of tertiary amines.

Neutralization reactions of sulfonic acids or fatty acids run spontaneously. Problems with the reaction can then arise when the reactants, i.e. H. Acids and alkalis, are not miscible with each other and / or if the resultant Neutralization product a solid or pasty substance is. In these cases, the quality of neutralization is determined by the  Intensity of reactant mixing and / or mixing of the reaction mixture determined.

The neutralization of sulfonic acids to wash-active sulfates or sulfonates is carried out discontinuously on an industrial scale Neutralization boilers or continuously in circulation circuits. In the latter case, the sulfonic acid is combined with the lye with intensive mixing by stirrers, centrifugal pumps and static mixing elements in already neutralized Product entered, the ratio of circulating current amount to freshly added sulfonic acid and lye in Range is from 10: 1 to 20: 1. More sensitive to hydrolysis during neutralization Products such as sulfuric acid half-star from Fatty alcohols and fatty alcohol ethers must be uniform good mixing and mixing of the neutralization mixture be guaranteed to rule out product loss. For removal the heat of reaction released is discontinuous and continuous driving heat exchange elements necessary to prevent product overheating can.

These processes allow neutralization products to be used a proportion of wash-active substance (WAS) of approx. 60% by weight produce. The majority of the remaining approx. 40% by weight is made up from water that is incorporated into the wash-active Sulfates / sulfonates in powder detergents such. B. by Spray drying must be removed.

A reduction in water content to reduce energy consumption when drying would be desirable and through the use of more concentrated alkalis in the neutralization reaction also feasible.

Simple material balances show that the neutralization  of sulfonic acids with 50% sodium hydroxide neutralization products with a share of washing-active substance of approx. 80% and have a water content of approx. 20%. The This also provides the energy balance of the neutralization reaction Result that about 40-50% of that during neutralization formed and with the 50% sodium hydroxide solution in the reaction mixture introduced water with the released Heat of reaction can be evaporated. Theoretically arise thus when using 50% sodium hydroxide solution the heat of reaction for drying neutralization products a share of about 90% detergent substance and only approx. 10% water. The neutralization products of sulfonic acids based on fatty alcohol and fatty acid esters are under These conditions can already be processed into free-flowing powders. By utilizing the heat of reaction, however, can also other, undesirable volatile substances from the products be removed. As an example here is the reduction of the Dioxane content in fatty alcohol ether sulfates called.

The process described above, used on an industrial scale for the neutralization of sulfonic acids allows the use of highly concentrated Do not leach, however, as this Neutralization product with increasing content of wash-active Substance becomes increasingly viscous and finally pasty. From a content of about 60 wt .-% detergent substance Sulfates / sulfonates barely pumpable, and an even one Mixing or mixing of the reaction components or Reaction mixture and the safe removal of the heat of reaction is no longer controllable.

Comparable to the neutralization of sulfonic acids for production wash-active sulfates / sulfonates is the manufacture of soaps by neutralizing fatty acids with alkalis. However, the neutralization process is not only carried out here  the pasty flow behavior of those formed during the reaction Soap difficult. Because the aqueous alkalis and the fatty acids are not soluble in one another is a correspondingly high one Degree of dispersion necessary to have a sufficiently large mass transfer area between the two liquid phases and thus to generate a sufficiently high reaction rate. The hitherto usual processes for the production of basic soaps Fatty acids can be divided into two process steps:

• 1. Merging, homogenizing or emulsifying each other insoluble reactants and performing the neutralization or saponification reaction in stirred tanks, reaction columns or loop reactors.
• 2. Multi-stage drying of the basic soap with an active substance content from approx. 60% to 80%.

The neutralization of fatty acids with lye is like neutralization of sulfonic acids with alkalis a spontaneous Reaction if it succeeds the two insoluble in each other Merge reactants sufficiently finely dispersed. The reaction can be started at room temperature, where a vigorous heating of the reaction mixture or Reaction products occurs.

As with the neutralization of sulfonic acids, the substance and energy balances for fatty acid neutralization that at Use of 50% sodium hydroxide to produce a basic soap with an active substance content of approx. 80% and approx. 20% Water content is possible in a single process step.

Instead of pure fatty acids, fatty acid methyl esters can also be used converted to soaps by saponification with sodium hydroxide solution will. This reaction produces methanol as a by-product,  that are removed from the basic soap or fine soap got to. This is generally done by evaporation or Stripping with steam. The manufacturing processes used of soaps from methyl esters correspond to the processes for Production of soaps from fatty acids, with an additional Process step, the removal of methanol, is necessary. in the The difference to fatty acid neutralization is the sales speed the methyl ester saponification strongly from the reaction temperature dependent. While at room temperature the Saponification reaction progresses slowly, it will be through higher temperatures (e.g. 100 ° C) accelerated strongly. they runs practically at the moment if it succeeds at 130-140 ° C, the methyl ester and the alkali finely dispersed in contact bring.

EP-A 00 83 122 describes a method of the type mentioned at the beginning Kind known, according to which two reactant streams, consisting each from acid and alkali, and independently of it a gas stream be fed to a spray nozzle; the neutralization reaction between the sprayed reactants takes place after leaving the nozzle. The mass ratio between gas and reactants is about 0.4. However, the procedure can only be narrow within Process parameters are operated when a high degree of neutralization reached and prevents the spray nozzles from becoming blocked shall be. In addition, the known method requires complicated constructed nozzles with a variety of concentric arranged channels for the separate supply of reactants and gaseous medium.

The invention is based on a method of the type mentioned directed, which requires sprayers of simple construction, with variable output over a wide range can be operated (e.g. 1.5 to 200 kg / h product for one of the nozzles used in the method of the invention),  and that is less prone to malfunction, because the Spray device is avoided.

This object is achieved in that the separate reactant streams, if necessary after heating, in each case charged with a gaseous medium, then merges and finally by using the spray device a speed of 0.1 to 15 m / sec, calculated from the gas-free reactant flows and based on the free cross-section the sprayer, presses, the masses of Reactants and gaseous medium are dimensioned so that a mass ratio of gaseous medium to product stream between 0.04 and 0.3 (kg / kg).

The method of the invention can be used anywhere where in the course of rapid chemical reactions solid or pasty products are formed, e.g. B. in neutralization of acids, especially carboxylic acids, sulfuric acid half-esters and sulfonic acids and in the saponification of Esters, e.g. B. low alkyl esters of fatty acids, in particular to the corresponding alkali salts using concentrated aqueous alkalis. The method of Invention for the production of alkali salts, in particular Sodium salt, monochloroacetic acid and for the preparation of quaternary ammonium compounds by alkylation of tertiary Amines, e.g. B. with alkyl halides. The is particularly preferred Use of the method of the invention in manufacture solid, free-flowing, wash-active products.

The solid or paste-like detergent products which can be produced according to the invention include, among others, the neutralization products of alkylarylsulfonic acids, α- sulfofatty acid esters and fatty acids and the sulfuric acid semiesters of alkoxylated, especially ethoxylated fatty alcohols and phenols and sulfosuccinic acid, as well as the saponification products of fatty acid esters, especially fatty acid methyl esters. The neutralization or saponification is preferably carried out with concentrated aqueous alkalis, for. B. with about 50 wt .-% NaOH containing sodium hydroxide solution. Gases which are inert to the reactants and reaction products, such as air, nitrogen and water vapor, are particularly suitable as the gaseous medium. Water vapor is used in particular when the reactant streams or one of the reactant streams are to be heated before being brought together. The distance between the place where the gas-charged reactant streams are brought together from the spraying device depends on the process conditions and material systems and should be kept as small as possible. It can be determined by a person skilled in the art using simple experiments; care should only be taken to avoid clogging of the nozzle due to neutralization or saponification reactions which start too early.

Aqueous alkalis for the purposes of the invention include in particular hydroxides, carbonates and hypochlorites of sodium and potassium in aqueous solution or suspension and their Understand mixtures. With the hypochlorites you can at the same time a bleaching effect desired for many products achieve.

The upper limit of the speed of the merged Reactant flows, based on the free cross section of the Spray device, results from the speed of sound of the gas and the set ratio of gas mass flow / Product mass flow. When calculating them, the gas-free reactant flows.

By adding a gaseous medium to the reactant streams  before they are merged, the process of Invention regardless of the type and construction of the spray nozzles used in each case; it is even a spray neutralization or saponification possible using a simple pipe. To achieve good mixing and to achieve one completely neutralized, homogeneous product are spraying with a pipe, of course, higher mass ratios between gaseous medium and product flow necessary as when using nozzles that are also used to atomize Liquids are used. Suitable for this are, for. B Hollow cone, full cone and flat jet nozzles with corresponding Swirl bodies or swirl slots or with a tangential one Inlet in a swirl room.

Suitable nozzle types and dimensions are given in the relevant literature, e.g. B. in K. Chaster, Spray Drying Handbook, John Wiley & Sons, New York 1979.

The dimensioning of the nozzle opening depends on the desired one Throughput.

The method of the invention is particularly suitable for Manufacture of solid, free-flowing, wash-active products, preferably for the production of wash-active alkali sulfates or sulfonates. Reactant streams are preferably used for this, especially acid flows, which are a solution or Suspension of buffer substances included. The kind of Buffer substances are more skilled in the field of hydrolysis Known surfactants.

According to a further advantageous embodiment of the invention is used to manufacture products that improve color need to be bleached, especially fatty acid (low) alkyl ester sulfonates, sodium perborate as a buffer substance  added; this buffer substance also acts as a bleach, so that, if necessary, to a further process stage can be dispensed with.

According to a further advantageous embodiment of the invention one uses the heat of neutralization or that of the saponification energy to be supplied by esters for Evaporation of the water of reaction or mostly via the amount of water supplied to aqueous alkalis, so that solid, pourable washable products can receive. Farther can the aforementioned neutralization heat or energy are used, contained or formed in the reaction system low-boiling solvents, e.g. B. methanol, completely remove.

A particularly advantageous feature of the method of the invention is based on the fact that in the production of Fatty alcohol ether sulfates through neutralization of sulfuric acid half-esters of fatty alcohol ethoxylates with aqueous Alkali receives products that - based on the solids content - Have dioxane levels below 200 ppm.

The method of the invention is also suitable for manufacture of alkali salts of substituted fatty acids Neutralization or of quaternary ammonium compounds Alkylation of the corresponding tertiary amines, in particular with alkyl halides.

An intensive process is achieved by the method of the invention Mixing of the reactants during their assembly and one that takes place immediately after the intensive mixing Fine distribution of the reaction mixture by spraying over a nozzle. The mixing and fine distribution can be done by kinetic energy of the reactants (flow velocity)  and by the potential energy of the reaction mixture (Pressure). Both processes are caused by the to be added favors gaseous medium. The admixture of the medium too the reactants before they are brought together prevents the formation larger product units at the meeting; this will provide the necessary micromixing of the reactants increased and the subsequent spraying process easier.

In the case of exothermic reactions, such as. B. in neutralization of sulfonic acids and fatty acids, the gaseous serves Medium, in addition to intensifying the mixing, also for removal the heat of reaction and to lower the reaction temperature. On the other hand, is a higher reaction temperature required to spray under the conditions to achieve high conversion rates, the reaction speed can increase that in addition to the reactant streams gaseous medium preheated and by direct heat exchange with the reaction mixture to adjust the necessary reaction temperature be used. As an example of this is the hydrolysis of fatty acid methyl esters with concentrated to name aqueous alkalis. The addition of the gaseous Medium in the reactant streams also enables the Formation of pasty or solid products when spraying small presses. The variation of the nozzle performance can over simple changes in the volume flows of the gaseous medium respectively.

In the practice of the method of the invention are the reactants stored in the corresponding templates dosed stoichiometrically using piston pumps in a no longer modified commercial nozzle or drove a spray pipe. Before the meeting of the The reactants are added immediately before the nozzle gaseous medium in the reactant streams. With neutralization  sulfonic and fatty acids are used as gaseous Medium air or nitrogen at room temperature. The Basic hydrolysis of the methyl ester can, for example, on the methyl ester side using nitrogen at room temperature and on the alkali side using superheated steam (150 to 160 ° C) as a gaseous medium.

The reaction temperature can be controlled directly via the sprayed mass or volume flows of the reactants and Temperature of the same happen. There is also an influence by the mass or volume flow of the gaseous Medium and the temperature of the same possible.

A regulation of the pH of the product in the technically interesting Range (pH 7 to pH 9) is due to the very small Amounts and residence times of the reactants in the nozzle and the strong dependence of the pH value on the mass ratio between acid and concentrated aqueous alkalis difficult. So z. B. a slight decrease in the used Amount of alkylbenzenesulfonic acid increased by 1% pH of the product from pH 4 to pH 11.

By adding buffers such as citric acid and in particular Sodium perborate (buffering effect of boric acid) results from the buffer effect a clear flattening of the neutralization curve.

For example, 6% sodium perborate to alkylbenzenesulfonic acid added and fed to the nozzle as a suspension, so only cause fluctuations in the reactant flows of 2% Changes in pH between 7 and 9.

The low is advantageous in the method described here Mass ratio between auxiliary and product. To  Achieve very good mixing and achieve one completely neutralized, homogeneous spray product are mass ratios of 0.3 kg, in particular less than 0.3 kg of gaseous medium per kg of finished product during manufacture a completely neutralized product during neutralization sufficient of sulfonic acids. The table below 1 shows the operating conditions when using different ones Nozzle types and nozzle diameters in the neutralization of Alkylbenzenesulfonic acid with 50% sodium hydroxide solution.  

Table 1

Operating conditions in the neutralization of alkylbenzenesulfonic acid

The method of the invention is more preferred below on the basis of Exemplary embodiments explained in more detail. One was used Schlick nozzle, model 942, with dimensions according to Table 1.

example 1 Spray neutralization of alkyl benzene acid (ABS)

Commitment:
ABS (base C _12/14 ), approx. 60 kg / h, t approx. 60 ° C; Sodium hydroxide solution with 50% by weight NaOH, t approx. 40 ° C
Spray pressure: 4.5 bar
N₂ requirement: 2 m³ / h

Spray product (figures in% by weight):
WHAT: 84.8
US: 1.6
Na₂SO₄: 0.8
H₂O: 11.5
pH: 9.6
(1% solution, based on WHAT)
Color number after Velcro: 59
(5% solution, based on WHAT, 4 cm cuvette, blue filter No. 42)

Example 2 Spray neutralization of fatty alcohol sulfonic acid (FAS)

Commitment:
FAS (Basis C _12/16 ), approx. 60 kg / h, t approx. 60 ° C; Sodium hydroxide solution with 50% by weight NaOH, t approx. 40 ° C
Spray pressure: 4.5 bar
N₂ requirement: 2 m³ / h

Spray product (figures in% by weight):
WHAT: 71.2
US: 8.6
Na₂SO₄: 6.3
NaCl: 0.1
H₂O: 12.6
pH: 9.5
(1% solution, based on WHAT)
Color number after Velcro: 63
(5% solution, based on WHAT, 4 cm cuvette, blue filter No. 42)

Example 3 Spray neutralization of fatty acid methyl ester sulfonic acid (MES)

Commitment:
MES (basis C _16/18 ), approx. 20 kg / h, t approx. 80 ° C; Sodium hydroxide solution with 48% by weight NaOH, t approx. 40 ° C
Spray pressure: 8.5 bar
N₂ requirement: 2 m³ / h

Spray product (figures in% by weight):
Mono: 52.3
Tue: 27.7
Mono + Di: 80.0
US: 6.4
Na₂SO₄: 6.2
Water: 10.3
pH: 9.0
(1% solution, based on WHAT)
Color number after Velcro: 305
(5% solution, based on WHAT, 4 cm cuvette, blue filter No. 42)

Example 4 Spray neutralization of fatty alcohol ether sulfonic acid (FAES)

Commitment:
FAES (base C _12/14 ; 2 mol EO) with 380 ppm dioxane, t approx. 30 ° C; Sodium hydroxide solution with 50% by weight NaOH, t approx. 30 ° C
N₂ requirement: 2 m³ / h
Spray pressure: 5 bar

Spray product (figures in% by weight):
WHAT: 77.2
US: 3.8
Na₂SO₄: 1.2
H₂O: 9.4
Dioxane: below 200 ppm
pH: 10.1
(1% solution based on WHAT)
Color number according to Velcro: 37
(5% solution, based on WHAT; 4 cm cuvette, blue filter No. 42)

Example 5 Spray neutralization of fatty acid

Commitment:
Palmitic acid, 60 kg / h, t 70 ° C; Sodium hydroxide solution with 42% by weight NaOH, t 40 ° C
Spray pressure: 3.5 bar
N₂ requirement: 2 m³ / h

Spray product (figures in% by weight):
Na soap: 69.9
H₂O: 26.8
Palmitic acid: 0
pH: 9.7
(1% solution or Na soap)

Example 6 Saponification of fatty acid methyl esters

Commitment:
C₁₄ methyl ester, 30 kg / h, t 125 ° C; Sodium hydroxide solution with 50% by weight NaOH, t 110 ° C
Spray pressure: 6.5 bar
N₂ requirement: 1 m³ / h
Steam requirement: 1 m³ / h
Nozzle temperature (preheating 150 ° C)

Spray product (figures in% by weight):
Na soap: 86.6
H₂O: 13.7
C₁₄ methyl ester: 0.1-0.2
Methanol: 2.0
pH: 9.3
(1% solution, Na soap)

Claims (11)

1. A process for the production of solid or pasty products by reacting stoichiometric amounts of several reactants in a rapid reaction and spraying the reaction products in a spray device, characterized in that the separate reactant streams, if appropriate after heating, are each acted upon with a gaseous medium, then merges and finally presses through the spray device at a speed of 0.1 to 15 m / sec, calculated from the gas-free reactant streams and based on the free cross section of the spray device, the masses of reactants and gaseous medium being such that a mass ratio of gaseous medium to product flow between 0.04 and 0.3 (kg / kg) results. 2. The method according to claim 1, characterized in that one Neutralized acids with concentrated aqueous alkalis. 3. The method according to claim 1, characterized in that one Saponified esters with concentrated aqueous alkalis. 4. The method according to any one of claims 1 to 3 for the production solid, free-flowing, wash-active products. 5. The method according to any one of claims 1 to 4 for the production of wash-active alkali sulfates or sulfonates, thereby characterized in that one of the reactant streams, in particular the acid flow, a solution or suspension of buffer substances contains. 6. The method according to claim 5, characterized in that one sodium perborate is used as buffer substance. 7. The method according to any one of claims 1 to 6 for the production solid, free-flowing, wash-active products. 8. The method according to any one of claims 1 to 7 for the production of products that are free of low-boiling solvents are. 9. The method according to any one of claims 1 to 8 for the production of fatty alcohol ether sulfates with a dioxane content of less than 200 ppm, based on solids content, by neutralization of sulfuric acid half-esters of fatty alcohol ethoxylates with aqueous alkalis.   10. The method according to claim 1, characterized in that one Monochloroacetic acid reacted with concentrated alkali. 11. The method according to claim 1, characterized in that tertiary amines alkylated.